An exemplary conventional device for air-cooling an electronic apparatus will be described with reference to FIG. 5. An upper housing 1 and a lower housing 2 illustrated in FIG. 5 are coupled to sandwich a chassis 3 and constitutes a housing that contains an electronic apparatus. Suction openings 4, 4 are provided in each of the upper housing 1 and the lower housing 2; and a discharge opening 5 is provided in the chassis 3, or the upper housing 1 and the lower housing 2. A fan 6 is secured to the chassis 3.
Further, bosses 3a, 3a, . . . and radiation fins 3b, 3b, . . . are formed in the chassis 3; and printed boards 8, 8, . . . are fastened to the bosses 3a, 3a, . . . . Heat produced by a maximum-heat-producing part 9 mounted on the printed boards 8, 8, . . . is transmitted via the heat transmitting parts to the chassis 3.
Airflow indicated by the arrow, traveling from the suction openings 4, 4 to the discharge opening 5 is generated by the fan 6. This airflow cools down the chassis 3 and heat-producing electronic parts including the maximum-heat-producing part 9 mounted on the printed boards 8, 8 . . . .
According to the conventional device for air-cooling an electronic apparatus illustrated in FIG. 5, air flows via the suction opening into the inside of the housing and circulates in the inside of the housing. Along with air, dust also enters the inside of the housing, so that dust accumulates in the printed boards 8, 8, . . . and the like. Accordingly, maintenance must be regularly performed to remove the dust. If no maintenance is performed, dust causes the parts in the inside of the housing to be short-circuited, thus causing a failure.
In order to prevent dust from entering the inside of the housing, a dustproof filter may be installed in the suction openings 4, 4 of the air-cooling device illustrated in FIG. 5. However, such an air-cooling device is not suitable for a model having a large amount of heat production because clogging of the filter reduces air-intake to lower the capacity for cooling.
FIG. 6 illustrates an exemplary conventional device for air-cooling an electronic apparatus which allows for dustproof performance. In this example, an upper housing 1 and a lower housing 2 are mounted in the upper and lower parts of a chassis 3, respectively, so that an upper-side space and a lower-side space are formed. Printed boards 8, 8 arranged in the upper-side sealed space are fastened to bosses 3a, 3a, . . . of the chassis 3. Heat produced by a maximum-heat-producing part 9 mounted on the printed boards 8, 8, . . . is transmitted via the heat transmitting parts to the chassis 3.
Suction opening 4 and discharge openings 5, 5 are arranged in the lower housing 2. Airflow indicated by the arrow, traveling from the suction openings 4 to the discharge openings 5, 5 is generated by the fan 6 secured to the upper side of the suction opening 4. This airflow cools down radiation fins 3b, 3b, . . . of the chassis 3. The air in a space where the printed boards 8, 8 are contained is cooled via the chassis 3, and this air cools down electronic parts mounted on the printed boards 8, 8.
According to the conventional device for air-cooling an electronic apparatus illustrated in FIG. 6, accumulation of dust on the printed boards 8, 8 can be prevented. In this structure, however, stationary air surrounding the printed boards 8, 8 are cooled via the chassis 3, so sufficient capacity for cooling is not obtained; the temperature of air surrounding the printed boards 8, 8 rises to raise the temperature of electronic parts mounted on the printed boards 8, 8 thus shortening the life of the electronic parts.
In order to raise the capacity for cooling of the device for air-cooling an electronic apparatus illustrated in FIG. 6, the volume of the chassis 3 acting as a heat radiator and the volume of the sealed space must be increased, thus increasing the size of the electronic apparatus. In this case, improvement can be made by increasing the volume of air sent by the fan. In either case, however, the device is disadvantageous in space saving and manufacturing cost.
For example, a heat-releasing structure for an apparatus described in paragraphs [0013] to [0027], and illustrated in FIGS. 1 to 9 of Japanese Patent Application Laid-Open No. 2002-353677 satisfies the temperature conditions of a heat-producing body irrespective of whether the structure has a horizontal position or a vertical position, but includes no specific means for raising the dustproof performance and the capacity for cooling.
The present invention has been achieved in view of the above problems and has an object to provide a device for air-cooling an electronic apparatus which has increased capacity for cooling a heat-producing part without increase in the size of the device, and in the device, accumulation of dust on the heat-producing part can be prevented.